Can someone paraphrase each line in this Keats Italian Sonnet?

The poem is "On First Looking into Chapman's Homer." George Chapman was a British author whose works included translations into English of the ancient Greek poet Homer. Keats says, in essence, "I've read a lot of great literature, and I've often heard praise of Homer's work, but I never really got how great Homer was until I read him in Chapman's translation. The excitement that I felt as I discovered Homer's greatness was like the excitement an astronomer must feel as he discovers a new planet, or that an explorer must feel when he sees a new ocean for the first time." (Keats makes a mistake in line 11. The explorer he's thinking of is Balboa, not Cortez.)